1. Field of the Invention
The present invention relates to an electric isolation transmission scheme, and more particularly to a method and an apparatus used for electric isolation transmission.
2. Description of the Prior Art
Please refer to FIG. 1, which illustrates a diagram of a conventional power system. The conventional power system utilizes an isolation transformer to implement electric isolation between the primary side and the secondary side. Please refer to FIG. 2, which shows a diagram illustrating a leakage current (i.e. a touch current) due to the isolation transformer in the conventional power system. As shown in FIG. 2, the driving source of the leakage current is a power source having a frequency of 50/60 Hz. In practical applications, parasitic capacitance CK exits between the primary side and the secondary side of the isolation transformer. This results in a worse performance of the electric isolation between the primary side and the secondary side. Usually, the parasitic capacitance CK is small enough, so the generated leakage current is also small and is still safe for use.
In order, however, to satisfy the requirement of electric isolation enhancement between the primary side and the secondary side, it is necessary to apply a double insulation scheme to the conventional isolation transformer. Accordingly, it is impossible to make the size of the conventional isolation transformer (i.e. the thickness of the device) become thinner. In addition, due to copper and iron losses, it is hard to improve the power transmission efficiency.